A standard for the short-range wireless interconnection of cellular phones, computers, and other electronic devices

Bluetooth is an open wireless technology standard for exchanging data over short distances (using short wavelength radio transmissions) from fixed and mobile devices, creating personal area networks (PANs) with high levels of security.

A short-range radio build into smartphones that lets you connect headsets, speakerphones or even computers to your smartphone.

These fit nicely against your ear and don't allow for sound to bother those around you. Additionally, you won't hear much sound from outside the headphones while wearing them. They were super comfy, too. (Shown with Samsung Galaxy Tab)